End-stage renal disease (ESRD) was inevitably fatal until the development of an external shunt together with the use of dialysis technology. According to the NIH, the incidence of treated ESRD in the US is rising 7.8% per year. Over 200,000 ESRD patients are presently being treated with hemodialysis through a graft/vein shunt. Current experience has shown that these grafts typically fall in 14-19 months. Clinically, most graft failures are secondary to thrombosis resulting from stenosis at the graft/vein anastomosis. Stenosis is the result of a cellular proliferation similar to that observed following other vascular interventions, including angioplasty and synthetic bypass graft placement. Similar intimal hyperplasia responses to vascular interventions (e.g. angioplasty) have been recently treated with ionizing radiation. Nearly all of the methods thus far proposed treat arterial vessels from the inside. Stenotic lesions are frequently eccentric within the vessel lumen, and proliferation is believed to be initiated in the smooth muscle cells near the adventitial layer of the vessel. It is proposed that an optimum prophylactic treatment for the threatened stenosis would deliver therapeutic levels of ionizing radiation over an extended period of time via a device that is positioned around the vessel/graft junction at the time of graft implant surgery. An external "wrap-around" source of radiation provides far greater spatial uniformity of dose in the treatment zone than an internal source. The selection of backing is important for minimizing dose to other tissue and to the physician. Only a single procedure is required to install both the graft and the wrap. PROPOSED COMMERCIAL APPLICATIONS: End-stage renal disease is treated with dialysis technology using an external shunt for access. The shunt graft frequently fails within a year due to low blood flow caused by stenosis. This proposal describes a method for inhibiting stenosis, significantly reducing revision surgeries and trauma to the patient.